It occurs to me that it might be possible to use the Arkham Horror board(s) with Mansions in an effort to develop new scenarios. Using the AH board as the "Big Map", and then zooming into a location using the Mansions tiles as the "Detailed" view. It would still play as Mansions, but give you a much larger landscape to work with. You would put together mini-encounters at certain locations, with clues to the overall objective, that would eventually lead players to the climax location to stop whatever cataclysm is occurring.

Not every AH location would have encounters, some could simply be closed and this would be identified on the board with a token, so players wouldn't waste their time in those locations. Some could simply be there to be used for the benefit of the players (or possibly the keeper too, we'll see) like buying new equipment at the shop, or healing at the hospital, or searching for ancient tomes in the library. They could either have a paragraph describing the location with what actions are available there, or move into a zoomed view with the Mansion tiles, so the players could search there for clues.

Players turns would still be 2 movements and an action, the keeper could summon to the big board as well as the small ones. There are many possibilities, and it would probably need a few regular Mansions expansions in order to pull it off (so that you have more rooms and more monsters to work with) but with scenarios designed properly you could pull off an amazing game, I think. I’m going to have to flesh it out, there are obstacles to overcome, any thoughts?
 

Sounds really awesome!

Sounds great. :)

I am also working on a game that uses both boards.

I imagine this would be a heck of a long game... event cards would have to have really long timers to be fair. But it does sound awesome, can't complain about that. Also, I suspect you'd need one gigantic table to pull it all off.

Possibly a slightly more manageable option would be to use just an expansion board, instead of the base game's behemoth.

Also, you may consider looking at the Arkham Casebooks site which has a slightly similar idea, but with a "choose your own adventure" companion booklet to handle the encounters.

Right. Although arkham investigations is a kind of a different game (which I really enjoy) and it would easily use both boards.

I was more thinking about a game based on AH main board where some encounters are small MoM board which unfold as you get in. Many things need to be polished, especially about the rules that quite differ between both games. 

My first step will be the introduction of a keeper into AH, to replace the mythos deck.

Here is a first version --still under development (obviously)-- that introduces a keeper to Arkham Horror (and keeps several aspects of the game flow that I like in MoM). This is intentionnaly NOT story driven. It is in the spirit of Arkham Horror standard game (and not MoM or Arkham Investigations which are plot driven). The main idea was to introduce a keeper in Arkham Horror. All comments on this very early version are most welcome.

Please note that only the 6 first Action cards are needed to play this variant. The three on the bottom are just examples of alternatives actions.

amikezor said:

Interresting but shouldn't it be a bit more expensive to open a gate? In a 4 player game you would be able to open one rare gate every turn. I think there is a risk that the investigators will lose due to too many gates open.

 After a first  play test that went well, I updated the cards and rules (e.g. there is a second sets of cards). I won't post it anymore here. Any further development will be posted here.